Bright days ahead for the Amiga world. AROS is doing well, AmigaOS4 is getting one heck of a machine in the AmigaOne X1000, and MorphOS continues its development at a brisk pace. Version 2.6 of MorphOS, currently in development, will add support for (G4, I'm assuming) PowerMacs, which, alongside support for the Mac Mini and eMac, gives MorphOS a solid base of used hardware to run on.

-PowerPC is dead for desktop use. Apple ditched it when its power management performance became unsatisfactory, and Sony remotely killed OtherOS on the PS3 because they feared some random piracy danger and actually thought that average people would actually go as far as installing linux on their PS3 in order to pirate games (well, it's Sony after all). The only remaining PowerPC desktops are legacy hardware that you'll likely be unable to replace once it wears out.

-This makes x86(_64) the only widespread desktop computer architecture, since other architectures (SPARC, ARM...) have not much presence on that market (should I say "yet" about ARM ?)

-Hence people replacing their dead PowerPC hardware will likely buy x86 hardware next, making x86 support more of a priority than legacy G4s

Thank you, that makes a lot more sense than just "Wow".
However, would people who buy a brand new x86 PC that comes with a Windows license be more likely to run Windows or MorphOS? Does it make sense for MorphOS to compete with Windows on x86?

Anyway I think Sony cut off OtherOS support because they subsidy the console. They sell it for less than its cost and recoup by selling expensive games.
If you buy the console to install linux, you won't be buying any game and that costs Sony the price of the subsidy.
Look at that: http://arstechnica.com/security/news/2009/11/sony-still-subsidizing...
That happened not long before Sony axed OtherOS. I suppose they didn't want that to become a trend.